The long-suffering U.S. steel industry applauded the Trump administration's announcement Thursday that it was opening an investigation into whether steel imports were hurting national security.

Steel Manufacturers Association President Philip K. Bell said it was "gratifying to see both steel companies and organized labor taking a solution-focused approach to address this issue."

"By invoking this portion of U.S. trade law, Section 232 of the Trade Expansion Act of 1962, to determine if imports of steel into the United States should be restricted on national security grounds, the president appears to be using every tool in his presidential toolkit to support 21st-century steelmaking," Bell said. The association represents 25 steelmakers that account for 75 percent of U.S. steel production.

Leo Gerard, president of the United Steelworkers union, said the investigation has the potential to "re-energize" domestic production, adding that it was "about time that action like this was initiated."

"This study, once completed, will give the president the justification to act to protect our national security, and to stop the predatory and protectionist imports from flooding our shores and decimating our productive capacity," Gerard said.

On Thursday, Commerce Secretary Wilbur Ross announced that the administration was opening an investigation into whether steel imports were hurting national security. Ross vowed to "conduct this investigation thoroughly and expeditiously so that, if necessary, we can take actions to defend American national security, workers, and businesses against foreign threats."

The announcement could lead to duties driving up foreign steel prices, but Ross stressed that the investigation was still in its early stages. "No decision has been made to take any concrete actions as yet."

The announcement could mean relief for domestic steel producers but trouble for companies that import it. Imports represent 26 percent of the steel market and domestic mills and foundries are operating at just 71 percent of capacity, the department reported.

Gerard cautioned that the administration would have to keep up the pressure for the effort to work. "Our trade laws are fundamentally broken and workers bear the brunt of the impact. If this approach does not work in addressing China's overcapacity, its predatory practices and the impact of its policies and those of other countries on our market, radical action will be necessary."